Interconnection structure, method of fabricating the same, and semiconductor package including interconnection structure

ABSTRACT

Disclosed are interconnection structures, semiconductor packages including the same, and methods of fabricating the same. The interconnection structure comprises a first dielectric layer, a wiring pattern formed in the first dielectric layer, a portion of the wiring pattern exposed with respect to a top surface of the first dielectric layer, a second dielectric layer on the first dielectric layer, the second dielectric layer including an opening that exposes the exposed portion of the wiring pattern, a pad formed in the opening of the second dielectric layer, the pad including a base part that covers the exposed portion of the wiring pattern at a bottom of the opening and a sidewall part that extends upwardly along an inner lateral surface of the opening from the base part, a first seed layer interposed between the second dielectric layer and a first lateral surface of the sidewall part, the first seed layer being in contact with the first lateral surface and the second dielectric layer, and a second seed layer that conformally covers a second lateral surface of the sidewall part and a top surface of the base part, the second lateral surface being opposite to the first lateral surface the second dielectric layer.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. nonprovisional application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2020-0109118 filed on Aug. 28,2020 in the Korean Intellectual Property Office, the disclosure of whichis hereby incorporated by reference in its entirety.

BACKGROUND

The present inventive concepts relate to an interconnection structureand a semiconductor package including the same.

Semiconductor chips are gradually becoming compact with the continuousdevelopment of semiconductor technology. In contrast, various functionsare integrated into a single semiconductor chip. Therefore,semiconductor chips have a great number of input/output pads on a smallarea.

A semiconductor package is provided to implement an integrated circuitchip to qualify for use in electronic products. A semiconductor packageis typically configured such that a semiconductor chip is mounted on aprinted circuit board and bonding wires or bumps are used toelectrically connect the semiconductor chip to the printed circuitboard. Various studies are conducted to improve structural stability andelectrical properties without pattern abnormality.

SUMMARY

Some example embodiments of the present inventive concepts provide aninterconnection structure with improved structural stability and asemiconductor package including the same.

An object of the present inventive concepts is not limited to thementioned above, and other objects which have not been mentioned abovewill be clearly understood to those skilled in the art from thefollowing description.

According to some example embodiments of the present inventive concepts,an interconnection structure may comprise: a first dielectric layer; awiring pattern formed in the first dielectric layer, a portion of thewiring pattern exposed with respect to a top surface of the firstdielectric layer; a second dielectric layer on the first dielectriclayer, the second dielectric layer including an opening that exposes theexposed portion of the wiring pattern; a pad formed in the opening ofthe second dielectric layer, the pad including a base part that coversthe exposed portion of the wiring pattern at a bottom of the opening anda sidewall part that extends upwardly along an inner lateral surface ofthe opening from the base part; a first seed layer interposed betweenthe second dielectric layer and a first lateral surface of the sidewallpart, the first seed layer being in contact with the first lateralsurface and the second dielectric layer; and a second seed layer thatconformally covers a second lateral surface of the sidewall part and atop surface of the base part, the second lateral surface being oppositeto the first lateral surface.

According to some example embodiments of the present inventive concepts,a semiconductor package may comprise: a redistribution substrate; asemiconductor chip mounted on the redistribution substrate; a moldinglayer on the redistribution substrate, the molding layer covering thesemiconductor chip; and an external terminal below the redistributionsubstrate. The redistribution substrate may include: a first dielectriclayer; a wiring pattern formed in the first dielectric layer andelectrically connected to the semiconductor chip, a portion of thewiring pattern exposed with respect to a bottom surface of the firstdielectric layer; a second dielectric layer formed on the firstdielectric layer and including an opening that exposes the exposedportion of the wiring pattern; a pad formed in the opening of the seconddielectric layer, the pad being in contact with the external terminal,the pad having a recess region that is recessed toward the firstdielectric layer from a first surface of the pad opposite the firstdielectric layer; and a first seed layer that conformally covers therecess region and the first surface of the pad, the first seed layerextending between the pad and the second dielectric layer.

According to some example embodiments of the present inventive concepts,a method of fabricating an interconnection structure may comprise:forming a sacrificial pattern on a carrier substrate; forming on thecarrier substrate a first dielectric layer that has an opening, thesacrificial pattern being in the opening; forming on the carriersubstrate a first seed layer that conformally covers the sacrificialpattern, a top surface of the first dielectric layer, and an innerlateral surface and a bottom surface of the opening; forming on thefirst seed layer a conductive layer that covers the first dielectriclayer and fills the opening; performing on the conductive layer aplanarization process to form a pad that remains in the opening and toselectively remove the first seed layer from the top surface of thefirst dielectric layer; forming a second dielectric layer on thepassivation layer; and forming a wiring pattern that penetrates thesecond dielectric layer and is coupled to the pad.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view showing an interconnectionstructure according to some example embodiments of the present inventiveconcepts.

FIG. 2 illustrates an enlarged view showing section A of FIG. 1.

FIG. 3 illustrates a plan view showing a first seed layer and a secondseed layer.

FIG. 4 illustrates a cross-sectional view showing an interconnectionstructure according to some example embodiments of the present inventiveconcepts.

FIG. 5 illustrates an enlarged view showing section B of FIG. 4.

FIG. 6 illustrates a cross-sectional view showing an interconnectionstructure according to some example embodiments of the present inventiveconcepts.

FIG. 7 illustrates an enlarged view showing section C of FIG. 6.

FIG. 8 illustrates a plan view showing a first seed layer and a secondseed layer.

FIGS. 9 to 12 illustrate cross-sectional views showing a semiconductorpackage according to some example embodiments of the present inventiveconcepts.

FIGS. 13 to 23 illustrate cross-sectional views showing a method offabricating an interconnection structure according to some exampleembodiments of the present inventive concepts.

FIGS. 24 to 28 illustrate cross-sectional views showing a method offabricating an interconnection structure according to some exampleembodiments of the present inventive concepts.

DETAILED DESCRIPTION OF EMBODIMENTS

The following will now describe an interconnection structure accordingto the present inventive concepts with reference to accompanyingdrawings.

FIG. 1 illustrates a cross-sectional view showing an interconnectionstructure according to some example embodiments of the present inventiveconcepts. FIG. 2 illustrates an enlarged view showing section A ofFIG. 1. FIG. 3 illustrates a plan view taken along line I-I′ of FIG. 1,showing a first seed layer and a second seed layer.

Referring to FIGS. 1 to 3, an interconnection structure 100 may includeat least one redistribution layer 110 and substrate pads 120 provided onthe redistribution layer 110. The present embodiment will discuss that asingle redistribution layer 110 is provided, but the present inventiveconcepts are not limited thereto. The interconnection structure 100 mayinclude two or more redistribution layers 110 that are verticallystacked. In this description, the interconnection structure 100 may beused as an interconnection substrate, an interconnection layer, or aredistribution substrate each of which is used for a semiconductorpackage.

A first dielectric layer 102 may be provided. For example, the firstdielectric layer 102 may include or may be formed of a dielectric and/orphotosensitive polymer. The first dielectric layer 102 may have, on itsupper portion, internal pads 104 electrically connected to theredistribution layer 110 which will be discussed below. The internalpads 104 may be buried in the first dielectric layer 102. The internalpads 104 may be exposed on a top surface of the first dielectric layer102. The internal pads 104 may correspond to redistribution circuits orinternal circuits of a redistribution substrate to which theinterconnection structure 100 is applied. Alternatively, the internalpads 104 may correspond to pads of a redistribution substrate to whichthe interconnection structure 100 is applied and on which asemiconductor device or an electronic device is mounted.

In certain embodiments, a first passivation layer may be provided on thefirst dielectric layer 102. The first passivation layer may cover thetop surface of the first dielectric layer 102. In this case, theinternal pads 104 may penetrate the first passivation layer and may beexposed on a top surface of the first passivation layer.

Spatially relative terms, such as “top,” “bottom,” “beneath,” “below,”“lower,” “above,” “upper” and the like, may be used herein for ease ofdescription to describe one element's or feature's relationship toanother element(s) or feature(s) as illustrated in the figures. It willbe understood that the spatially relative terms are intended toencompass different orientations of the device in use or operation inaddition to the orientation depicted in the figures. For example, if thedevice in the figures is turned over, elements described as “below” or“beneath” other elements or features would then be oriented “above” theother elements or features as is the same in various embodiments in thepresent disclosure. Thus, the term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The redistribution layer 110 may be provided on the first dielectriclayer 102. The redistribution layer 110 may include a second dielectriclayer 112 and one or more first wiring patterns 114 in the seconddielectric layer 112.

The second dielectric layer 112 may be disposed on the first dielectriclayer 102. The second dielectric layer 112 may include or may be formedof a photosensitive polymer or a photo-imageable dielectric (PID). Forexample, the photosensitive polymer may include one or more ofphotosensitive polyimide, polybenzoxazole (PBO), phenolic polymers, andbenzocyclobutene polymers.

The first wiring patterns 114 may be provided in the second dielectriclayer 112. Each of the first wiring patterns 114 may have a damascenestructure. For example, the first wiring pattern 114 may have a linepart LP, and may also have a head part HP and a tail part TP that areintegrally formed into a single body. For example, the head part HP maycorrespond to or may be a pad part that is provided on a lower portionof the second dielectric layer 112 and is coupled to the internal pad104, and the tail part TP may correspond to or may be a via part thatpenetrates the second dielectric layer 112 and has connection with thehead part HP. The head part HP and the tail part TP may verticallyoverlap each other, and the tail part TP may extend from the head partHP onto a top surface of the second dielectric layer 112. The head partHP may have a width, e.g., in a horizontal direction, greater than thatof the tail part TP. The line part LP may have a linear shape. The linepart LP and the head part HP may be connected (e.g., integrally formed)to constitute an electrical circuit of the redistribution layer 110. Thefirst wiring pattern 114 may include or may be formed of a conductivematerial. For example, the first wiring pattern 114 may include or maybe formed of copper (Cu).

A first barrier layer 116 may be formed to surround the first wiringpattern 114. The first barrier layer 116 may be interposed between thesecond dielectric layer 112 and the first wiring pattern 114. The firstbarrier layer 116 may surround lateral and top surfaces of the firstwiring pattern 114. The first barrier layer 116 may have a thickness ofabout 50 Å to about 1,000 Å. The first barrier layer 116 may include ormay be formed of titanium (Ti), tantalum (Ta), titanium nitride (TiN),or tantalum nitride (TaN).

A first passivation layer 118 may be provided on the second dielectriclayer 112. The first passivation layer 118 may cover the top surface ofthe second dielectric layer 112. The tail part TP of the first wiringpattern 114 may penetrate the first passivation layer 118. Therefore,the first wiring pattern 114 may be exposed on a top surface of thefirst passivation layer 118.

A third dielectric layer 122 may be provided on the first passivationlayer 118. The third dielectric layer 122 may cover the top surface ofthe first passivation layer 118. The third dielectric layer 122 may haveopenings OP. The openings OP may vertically penetrate the thirddielectric layer 122, e.g., from a bottom to a top. The openings OP mayexpose the first wiring patterns 114. For example, portions of thewiring patterns 114 formed in the second dielectric layer 112 may beexposed with respect to a top surface of the second dielectric layer112, and the openings OP may expose the exposed portion of the wiringpattern 114. As shown in FIG. 3, the openings OP may have their circularshapes when viewed in a plan view. The present inventive concepts,however, are not limited thereto, and in certain embodiments, theopenings OP may have their polygonal, oval, or linear shapes when viewedin a plan view. The third dielectric layer 122 may include or may beformed of a photosensitive polymer or a photo-imageable dielectric(PID). For example, the photosensitive polymer may include one or moreof photosensitive polyimide, polybenzoxazole (PBO), phenolic polymers,and benzocyclobutene polymers. The third dielectric layer 122 mayprotect the redistribution layer 110, e.g., from physical and/orchemical damages including contaminations.

The third dielectric layer 122 may have substrate pads 120 therein. Thesubstrate pads 120 may be disposed in the openings OP of the thirddielectric layer 122. The substrate pads 120 may have U shapes at theircross-sections taken in a direction perpendicular to the top surface ofthe first dielectric layer 102. For example, the substrate pads 120 mayhave their shapes that extend along inner lateral and bottom surfaces ofthe openings OP. Each of the substrate pads 120 may have a base part 124positioned on the bottom surface of the opening OP and a sidewall part126 that extends in a direction perpendicular to the top surface of thefirst dielectric layer 102 and along the inner lateral surface of theopening OP. The sidewall part 126 may have a first lateral surface 126 adirected toward the inner lateral surface of the opening OP and a secondlateral surface 126 b opposite to the first lateral surface 126 a. Thesidewall part 126 may have a width, defined as a width between the firstand second lateral surfaces 126 a and 126 b, e.g., in a horizontaldirection, which is about 5% to about 20% of a width of the opening OP.When viewed in a plan view, a closed curved shape may be given to thesidewall part 126 that extends along the inner lateral surface of theopening OP. For example, the sidewall part 126 may have a ring shape.Therefore, an empty space may be formed on the base part 124 and insidethe sidewall part 126. For example, the substrate pads 120 may fill theopenings OP, and may be provided on their top surfaces with recessregions RS that are recessed toward the first dielectric layer 102 fromthe top surfaces of the substrate pads 120. The recess region RS mayhave a width about 80% to about 95% of that of the opening OP, e.g., ina horizontal direction. The substrate pad 120 may have a thickness ofabout 1 μm to about 10 μm, or a thickness of the base part 124 and athickness of the sidewall part 126. The thickness of the base part 124may correspond to a thickness in a direction perpendicular to a topsurface of the base part 124, and the thickness of the sidewall part 126may correspond to a thickness in a direction perpendicular to the firstlateral surface 126 a of the sidewall part 126. The substrate pads 120may include or may be formed of a conductive material. For example, thesubstrate pads 120 may include or may be formed of copper (Cu).

A first seed layer 142 may be interposed between the substrate pad 120and the third dielectric layer 122. For example, the first seed layer142 may be provided on the first lateral surface 126 a of the sidewallpart 126 included in the substrate pad 120. The first seed layer 142 maybe in contact with the inner lateral surface of the opening OP formed inthe third dielectric layer 122 and with the first lateral surface 126 aof the substrate pad 120. The first seed layer 142 may separate thesubstrate pad 120 from the third dielectric layer 122. The first seedlayer 142 may extend into the recess region RS. For example, the firstseed layer 142 may extend onto a top surface of the sidewall part 126,the second lateral surface 126 b of the sidewall part 126, and the topsurface of the base part 124. In this case, the first seed layer 142 mayconformally cover an outer lateral surface (or the first lateral surface126 a), the top surface, and an inner lateral surface of the substratepad 120. The first seed layer 142 may have an uppermost surface coplanarwith a top surface of the third dielectric layer 122. The first seedlayer 142 may have a thickness of about 0.1 μm to about 1 μm. The firstseed layer 142 may include or may be formed of titanium (Ti), titaniumnitride (TiN), tantalum (Ta), tantalum nitride (TaN), nickel (Ni), ortungsten nitride (TW). The first seed layer 142 may block oxygen frombeing introduced to the substrate pad 120 from the third dielectriclayer 122 and/or from outside, and may prevent the substrate pad 120from being corroded. For example, the first seed layer 142 may include ametallic material whose ionization tendency is greater than anionization tendency of a metallic material included in the substrate pad120.

It will be understood that when an element is referred to as being“connected” or “coupled” to or “on” another element, it can be directlyconnected or coupled to or on the other element or intervening elementsmay be present. In contrast, when an element is referred to as being“directly connected” or “directly coupled” to another element, or as“contacting” or “in contact with” another element, there are nointervening elements present at the point of contact.

A second seed layer 144 may be provided on the substrate pad 120. In therecess region RS, the second seed layer 144 be formed to conformallycover the top surface of the base part 124 included in the substrate pad120 and the second lateral surface 126 b of the sidewall part 126included in the substrate pad 120. For example, the first seed layer 142and the second seed layer 144 may be sequentially stacked on the basepart 124. In this case, the recess region RS may have therein the firstseed layer 142 interposed between the substrate pad 120 and the secondseed layer 144. For example, the first seed layer 142 may extend along atop surface of the sidewall part 126 and between the substrate pad 120and the second seed layer 144. The second seed layer 144 may have anuppermost end at the same level as that of the top surface of the thirddielectric layer 122 and that of the uppermost surface of the first seedlayer 142. The second seed layer 144 may have a U-shaped cross-sectionthat conformally covers an inner sidewall and a bottom surface of therecess region RS. The second seed layer 144 may have a thickness ofabout 0.1 μm to about 1 μm. The second seed layer 144 may include or maybe formed of a metallic material that has a high wettability with anexternal terminal 150 which will be discussed below. For example, thesecond seed layer 144 may include or may be formed of copper (Cu),ruthenium (Ru), nickel (Ni), titanium (Ti), or tungsten (W).

In certain embodiments, the first seed layer 142 and the second seedlayer 144 may be integrally formed, e.g., in the same process, so thatthe first seed layer 142 and the second seed layer 144 forms one body.In this case, the integrally formed seed layer may be thicker on therecess region RS than on the top surface of the sidewall part 126. Incertain embodiments, the integrally formed seed layer may havesubstantially the same thickness on the recess region RS and on the topsurface of the side wall part 126.

In certain embodiments, a third seed layer may be formed between thefirst seed layer 142 and the second seed layer 144. The third seed layermay be formed of the same material as one of the first and second seedlayers 142 and 144. In certain embodiments, the third seed layer may beformed of a different material than the first and second seed layers 142and 144.

Terms such as “same,” “equal,” “planar,” or “coplanar,” as used hereinwhen referring to orientation, layout, location, shapes, sizes,compositions, amounts, or other measures do not necessarily mean anexactly identical orientation, layout, location, shape, size,composition, amount, or other measure, but are intended to encompassnearly identical orientation, layout, location, shapes, sizes,compositions, amounts, or other measures within acceptable variationsthat may occur, for example, due to manufacturing processes. The term“substantially” may be used herein to emphasize this meaning, unless thecontext or other statements indicate otherwise. For example, itemsdescribed as “substantially the same,” “substantially equal,” or“substantially planar,” may be exactly the same, equal, or planar, ormay be the same, equal, or planar within acceptable variations that mayoccur, for example, due to manufacturing processes.

The substrate pads 120 may be provided thereon with external terminals150. Each of the external terminals 150 may be in contact with acorresponding second seed layer 144. For example, each of the externalterminals 150 may fill a remaining portion of the recess regions RS ofthe substrate pads 120. For example, the recess regions RS may be filledwith the first seed layers 142, the second seed layers 144 and/or theexternal terminals 150.

According to some example embodiments of the present inventive concepts,as the substrate pad 120 has a U-shaped cross-section, an increasedcontact area and a high adhesive force may be provided between thesecond seed layer 144 and the external terminal 150. In addition, as thesubstrate pad 120 is provided thereon with the second seed layer 144having a high wettability with the external terminal 150, the externalterminal 150 may be rigidly attached to the substrate pad 120.Accordingly, the interconnection structure 100 may be provided to haveincreased structural stability. For example, the second seed layer 144may have a wettability higher than the first seed layer 142 with respectto the external terminal 150. For example, the external terminal 150 maybe a solder ball.

According to some example embodiments, a second seed layer 144′ mayextend onto the sidewall part 126 of the substrate pad 120. FIG. 4illustrates a cross-sectional view showing an interconnection structure100 according to some example embodiments of the present inventiveconcepts. FIG. 5 illustrates an enlarged view showing section B of FIG.4. As shown in FIGS. 4 and 5, the second seed layer 144′ may extend fromthe second lateral surface 126 b of the sidewall part 126 onto the topsurface of the sidewall part 126. For example, the first seed layer 142and the second seed layer 144′ may be sequentially stacked on the topsurface of the base part 124. As the second seed layer 144′ extends ontothe sidewall part 126 of the substrate pad 120, the second seed layer144′ may have an uppermost surface at a higher level than that of thetop surface of the third dielectric layer 122. On the sidewall part 126,the second seed layer 144′ may have an end on the same plane on which acontact surface is provided between the third dielectric layer 122 andthe first seed layer 142.

The substrate pads 120 may be provided thereon with external terminals150. The external terminal 150 may be in contact with the second seedlayer 144′. For example, the external terminal 150 may fill a remainingportion of the recess region RS, e.g., after filled with the first seedlayer 142 and/or the second seed layer 144′.

According to some example embodiments of the present inventive concepts,the second seed layer 144′ may be provided to completely cover the topsurface of the substrate pad 120, and the external terminal 150 may bein contact with only the second seed layer 144′. For example, theexternal terminal 150 may be in contact with only a single materiallayer (e.g., in this example, with only the second seed layer 144′).Therefore, adhesion stress may be reduced between the substrate pad 120and the external terminal 150. For example, adhesion stress may beincreased when one pattern is attached with two or more differentpatterns formed of different materials. For example, an adhesion stressmay be caused by differences of adhesion forces and/or expansion ratesproduced when the external terminal 150 is in contact with a pluralityof material layers/patterns together. Accordingly, the presentembodiment may be beneficial to provide an interconnection structurewith improved structural stability.

FIG. 6 illustrates a cross-sectional view showing an interconnectionstructure 100 according to some example embodiments of the presentinventive concepts. FIG. 7 illustrates an enlarged view showing sectionC of FIG. 6. FIG. 8 illustrates a cross-sectional view taken along lineII-II′ of FIG. 6, showing a first seed layer and a second seed layer. Inthe embodiment that follows, a detailed description of technicalfeatures repetitive to those discussed with reference to FIGS. 1 to 5will be omitted, and a difference thereof will be discussed in detail.The same components as those of the interconnection structure 100discussed above will be allocated the same reference numerals thereto.

Referring to FIGS. 6 to 8, the first seed layer 142 may be interposedbetween the substrate pad 120 and the third dielectric layer 122. Forexample, the first seed layer 142 may be provided on the first lateralsurface 126 a of the sidewall part 126 included in the substrate pad120. The first seed layer 142 may be in contact with the inner lateralsurface of the opening OP in the third dielectric layer 122 and with thefirst lateral surface 126 a of the substrate pad 120. The first seedlayer 142 may separate the substrate pad 120 from the third dielectriclayer 122. The first seed layer 142 may extend into the recess regionRS. For example, the first seed layer 142 may extend onto a top surfaceof the sidewall part 126, the second lateral surface 126 b of thesidewall part 126, and the top surface of the base part 124. In thiscase, the first seed layer 142 may conformally cover an outer lateralsurface (or the first lateral surface 126 a), the top surface, and aninner lateral surface of the substrate pad 120. The first seed layer 142may have an uppermost surface coplanar with a top surface of the thirddielectric layer 122. The first seed layer 142 may have a thickness ofabout 0.1 μm to about 1 μm. The first seed layer 142 may block oxygenfrom being introduced to the substrate pad 120 from the third dielectriclayer 122 and/or from outside, and may prevent the substrate pad 120from being corroded. The first seed layer 142 may include or may beformed of a metallic material that has a high wettability with anexternal terminal 150. For example, the first seed layer 142 may includeor may be formed of ruthenium (Ru), nickel (Ni), titanium (Ti), ortungsten (W).

The second seed layer (see 144 of FIG. 1) may not be provided in thepresent embodiment.

The substrate pads 120 may be provided thereon with external terminals150. The external terminal 150 may be in contact with the first seedlayer 142. For example, the external terminal 150 may fill a remainingportion of the recess region RS of the substrate pads 120.

According to some example embodiments of the present inventive concepts,as the substrate pad 120 has a U-shaped cross-section, an increasedcontact area and a high adhesive force may be provided between the firstseed layer 142 and the external terminal 150. For example, as thesubstrate pad 120 is provided thereon with the first seed layer 142having a high wettability with the external terminal 150, the externalterminal 150 may be rigidly attached to the substrate pad 120.Accordingly, the shape of the substrate pad 120 may be beneficial toprovide an interconnection structure with improved structural stability.

FIG. 9 illustrates a cross-sectional view showing a semiconductorpackage according to some example embodiments of the present inventiveconcepts.

Referring to FIG. 9, a semiconductor package 10 may include a lowerredistribution substrate 100, a first semiconductor chip 200, and afirst molding member 300.

The lower redistribution substrate 100 may be the same as or similar toany one of the interconnection structures discussed with reference toFIGS. 1 to 8.

The lower redistribution substrate 100 may include redistribution layers110-1, 110-2, and 110-3 and substrate pads 120 provided below theredistribution layers 110-1, 110-2, and 110-3.

Each of the redistribution layers 110-1, 110-2, and 110-3 may correspondto the redistribution layer 110 discussed with reference to FIG. 1. Forexample, each of the redistribution layers 110-1, 110-2, and 110-3 mayinclude a lower dielectric layer 112 and a lower wiring pattern 114 inthe lower dielectric layer 112. The lower dielectric layer 112 mayinclude or may be formed of a photosensitive polymer or aphoto-imageable dielectric (PID). The lower wiring pattern 114 may beprovided in the lower dielectric layer 112. The lower wiring pattern 114may have a damascene structure. Each of the redistribution layers 110-1,110-2, and 110-3 may have a lower barrier layer 116 that covers lateraland bottom surfaces of the lower wiring pattern 114. Each of theredistribution layers 110-1, 110-2, and 110-3 may have a lowerpassivation layer 118 that covers a bottom surface of the lowerdielectric layer 112. The lower passivation layer 118 may cover anentirety of the bottom surface of the lower dielectric layer 112 and mayexpose the lower wiring pattern 114. FIG. 9 depicts the lowerredistribution substrate 100 having three redistribution layers 110-1,110-2, and 110-3, but the present inventive concepts are not limitedthereto. The lower redistribution substrate 100 may have various numbersof redistribution layers in certain embodiments. When a first layer orpattern covers a bottom surface of a second layer or pattern, thecovering configuration may include an arrangement that the first layeror pattern vertically overlaps the second layer or pattern in which thefirst layer or pattern is positioned below the second layer or pattern.

On an uppermost redistribution layer 110-3, the lower wiring pattern 114may be exposed on a top surface of the lower dielectric layer 112, andmay correspond to a pad of the lower redistribution substrate 100 onwhich a semiconductor or electronic device is mounted.

A substrate pad dielectric layer 122 may be provided on a bottom surfaceof a lowermost redistribution layer 110-1. The substrate pad dielectriclayer 122 may cover the lower dielectric layer 112 of the lowermostredistribution layer 110-1. The substrate pad dielectric layer 122 mayhave openings. The openings may vertically penetrate the substrate paddielectric layer 122, and may each expose the lower wiring pattern 114of the lowermost redistribution layer 110-1. The substrate paddielectric layer 122 may include or may be formed of a photosensitivepolymer or a photo-imageable dielectric (PID).

The substrate pad dielectric layer 122 may have substrate pads 120therein. The substrate pads 120 may be disposed in the openings of thesubstrate pad dielectric layer 122. The substrate pads 120 may havetheir shapes that extend along inner lateral and bottom surfaces of theopenings. For example, the substrate pads 120 may fill the openings, andmay be provided on their bottom surfaces with recess regions that arerecessed toward the redistribution layers 110-1, 110-2, and 110-3 fromthe bottom surfaces of the substrate pads 120. The substrate pads 120may include or may be formed of a conductive material. For example, thesubstrate pads 120 may include or may be formed of copper (Cu).

A first seed layer 142 may be interposed between the substrate pad 120and the substrate pad dielectric layer 122. For example, the first seedlayer 142 may be in contact with the inner lateral surface of theopening formed in the substrate pad dielectric layer 122 and with anouter lateral surface of the substrate pad 120. The first seed layer 142may separate the substrate pad 120 from the substrate pad dielectriclayer 122. The first seed layer 142 may extend into the recess region.For example, the first seed layer 142 may conformally cover the outerlateral surface, the bottom surface, and an inner lateral surface of thesubstrate pad 120. The first seed layer 142 may have a lowermost surfacecoplanar with a bottom surface of the substrate pad dielectric layer122. The first seed layer 142 may include or may be formed of titanium(Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN),nickel (Ni), or tungsten nitride (TW).

A second seed layer 144 may be provided on the substrate pad 120. In therecess region, the second seed layer 144 may be formed to conformallycover the inner lateral surface and the bottom surface of the substratepad 120. For example, the first seed layer 142 and the second seed layer144 may be sequentially stacked in the recess region. The second seedlayer 144 may have a reverse U-shaped cross-section that conformallycovers an inner lateral surface and a bottom surface of the recessregion. The second seed layer 144 may include or may be formed of ametallic material that has a high wettability with an external terminal150 which will be discussed below. For example, the second seed layer144 may include or may be formed of copper (Cu), ruthenium (Ru), nickel(Ni), titanium (Ti), or tungsten (W).

The substrate pads 120 may be provided thereon with external terminals150. The external terminal 150 may be in contact with the second seedlayer 144. For example, the external terminal 150 may fill a remainingportion of the recess region.

The first semiconductor chip 200 may be mounted on the lowerredistribution substrate 100. The first semiconductor chip 200 may beflip-chip mounted on the lower redistribution substrate 100. Forexample, the first semiconductor chip 200 may include chip pads 202electrically connected to integrated circuits of the first semiconductorchip 200. Connection terminals 204 may be provided between the chip pads202 and the lower wiring patterns 114 of the uppermost redistributionlayer 110-3. The chip pads 202 may be electrically connected through theconnection terminals 204 to the lower wiring patterns 114 of theuppermost redistribution layer 110-3. The first semiconductor chip 200may be, for example, a logic chip. Although not shown, an under-fillmember may fill a space between the first semiconductor chip 200 and thelower redistribution substrate 100. Between the first semiconductor chip200 and the lower redistribution substrate 100, the under-fill membermay surround the connection terminals 204, the chip pads 202, and thelower wiring pattern 114 of the uppermost redistribution layer 110-3.

A molding member 300 may be provided on the lower redistributionsubstrate 100. The molding member 300 may cover the first semiconductorchip 200. The molding member 300 may include or may be formed of adielectric material, such as an epoxy molding compound (EMC).

FIG. 10 illustrates a cross-sectional view showing a semiconductorpackage according to some example embodiments of the present inventiveconcepts.

Referring to FIG. 10, a semiconductor package 20 may include a lowerpackage BP and an upper package UP. For example, the semiconductorpackage 20 may be a package-on-package (PoP) in which the upper packageUP is mounted on the lower package BP.

The lower package BP may be similar to the semiconductor package 10discussed with reference to FIG. 9. For example, the lower package BPmay include a lower redistribution substrate 100, a first semiconductorchip 200 mounted on the lower redistribution substrate 100, and a firstmolding member 300 lying/formed on the lower redistribution substrate100 and covering the first semiconductor chip 200.

In addition, the lower package BP may further include a connectionsubstrate 400 and an upper redistribution substrate 500.

The connection substrate 400 may have an opening that penetratestherethrough. For example, the opening may be shaped like an open holethat connects top and bottom surfaces of the connection substrate 400.The bottom surface of the connection substrate 400 may be spaced apartfrom a top surface of the lower redistribution substrate 100. Theconnection substrate 400 may include a base layer 402 and a conductivemember as a wiring pattern provided in the base layer 402. For example,the base layer 402 may include or may be formed of silicon oxide. Theconductive member may be disposed closer than the opening to an outerportion of the connection substrate 400. The conductive member mayinclude upper pads 404, lower pads 406, and vias 408. The lower pads 406may be disposed on a lower portion, e.g., on a bottom surface, of theconnection substrate 400. The vias 408 may penetrate the base layer 402,and may electrically connect the lower pads 406 to the upper pads 404.For example, the connection substrate 400 may be formed of multiple baselayers 402. In this case, each of the base layers 402 may be providedwith vias 408, and a connection wire may be formed between the baselayers to electrically connect vias respectively formed in differentbase layers 402 as shown in FIG. 10.

The connection substrate 400 may be mounted on the lower redistributionsubstrate 100. For example, the connection substrate 400 may beconnected to the lower wiring patterns 114 of the uppermostredistribution layer 110-3 through connection substrate terminals 410provided on the lower pads 406. Therefore, the connection substrate 400may be electrically connected to the first semiconductor chip 200 andthe external terminals 150.

The first semiconductor chip 200 may be disposed on the lowerredistribution substrate 100. The first semiconductor chip 200 may bedisposed in the opening of the connection substrate 400. For example,the first semiconductor chip 200 may be coupled to the lower wiringpatterns 114 of the uppermost redistribution layer 110-3 throughconnection terminals 204 provided on the chip pads 202.

The upper redistribution substrate 500 may be disposed on a top surfaceof the first molding member 300 and the top surface of the connectionsubstrate 400. The upper redistribution substrate 500 may include afirst upper redistribution layer 510 and a second upper redistributionlayer 520 that are stacked on each other. The first and second upperredistribution layers 510 and 520 may be configured similarly to theredistribution layers 110-1, 110-2, and 110-3 of the lowerredistribution substrate 100. For example, the first upperredistribution layer 510 may include a first upper dielectric layer 512and one or more first upper wiring patterns 514 in the first upperdielectric layer 512, and the second upper redistribution layer 520 mayinclude a second upper dielectric layer 522 provided on the first upperdielectric layer 512 and one or more second upper wiring patterns 524 inthe second upper dielectric layer 522.

The upper redistribution substrate 500 may be coupled to the connectionsubstrate 400. For example, the first upper wiring patterns 514 of theupper redistribution substrate 500 may be coupled to the upper pads 404of the connection substrate 400. For example, the first upper wiringpatterns 514 of the upper redistribution substrate 500 may contact theupper pads 404 of the connection substrate 400.

The upper package UP may be mounted on the lower package BP. The upperpackage UP may include an upper package substrate 610, a secondsemiconductor chip 620, and a second molding member 630. The upperpackage substrate 610 may be a printed circuit board (PCB).Alternatively, the upper package substrate 610 may be a redistributionsubstrate. For example, the upper package UP may be the samesemiconductor package 10 as the one discussed with reference to FIG. 9.A first upper substrate pad 612 may be disposed on a bottom surface ofthe upper package substrate 610.

The second semiconductor chip 620 may be disposed on the upper packagesubstrate 610. The second semiconductor chip 620 may include integratedcircuits, and the integrated circuits may include a memory circuit, alogic circuit, or a combination thereof. The second semiconductor chip620 may be of a different type from the first semiconductor chip 200.The second semiconductor chip 620 may have an upper chip pad 622electrically connected through a bonding wire 624 to a second uppersubstrate pad 614 of the upper package substrate 610. FIG. 10 depictsthat the second semiconductor chip 620 is mounted on the upper packagesubstrate 610 in a wire bonding manner, but the second semiconductorchip 620 may be mounted in various ways, e.g., a flip chip mounting,etc.

The upper package substrate 610 may be provided thereon with the secondmolding member 630 that covers the second semiconductor chip 620. Thesecond molding member 630 may include or may be formed of a dielectricpolymer, such as an epoxy-based polymer.

A conductive terminal 616 may be disposed between the lower package BPand the upper package UP. The conductive terminal 616 may be interposedbetween and electrically connected to the first upper substrate pad 612and the second upper wiring pattern 524. Therefore, the upper package UPmay be electrically connected to the first semiconductor chip 200 andthe external terminal 150 through the conductive terminal 616, the upperredistribution substrate 500, and the connection substrate 400.

FIG. 11 illustrates a cross-sectional view showing a semiconductorpackage according to some example embodiments of the present inventiveconcepts.

Referring to FIG. 11, a semiconductor package 30 may include a lowerpackage BP′ and an upper package UP. For example, the semiconductorpackage 30 may be a package-on-package (PoP) in which the upper packageUP is mounted on the lower package BP′.

Compared to the semiconductor package 20 of FIG. 10, a connectionsubstrate 400 may not be included in the lower package BP′. The lowerpackage BP′ may include a conductive via 310. The conductive via 310 maybe laterally spaced apart from the first semiconductor chip 200. Theconductive via 310 may vertically penetrate the first molding member300. The conductive via 310 may be coupled to a lower wiring pattern 114of an uppermost redistribution layer 110-3 included in a lowerredistribution substrate 100. The conductive via 310 may be electricallyconnected through the lower redistribution substrate 100 to an externalterminal 150 or a first semiconductor chip 200. The conductive via 310may be coupled to a first upper wiring pattern 514 of an upperredistribution substrate 500. The conductive via 310 may include a metalpillar.

FIG. 12 illustrates a cross-sectional view showing a semiconductorpackage according to some example embodiments of the present inventiveconcepts.

Referring to FIG. 12, a semiconductor package may include a packagesubstrate 800, a redistribution substrate 100, a first semiconductorchip 200, and chip stacks ST. In the present embodiment, theredistribution substrate 100 may serve as an interposer and may becalled a redistribution interposer.

The redistribution interposer 100 may be the same as or similar to oneof the interconnection structures discussed with reference to FIGS. 1 to8. The redistribution interposer 100 may include redistribution layers110-1, 110-2, and 110-3 and substrate pads 120 provided below theredistribution layers 110-1, 110-2, and 110-3.

Each of the redistribution layers 110-1, 110-2, and 110-3 may include alower dielectric layer and a lower wiring pattern formed in the lowerdielectric layer.

A substrate pad dielectric layer 122 may be provided on a bottom surfaceof a lowermost redistribution layer 110-1. The substrate pad dielectriclayer 122 may cover the lowermost redistribution layer 110-1. Thesubstrate pad dielectric layer 122 may have openings. The openings mayvertically penetrate the substrate pad dielectric layer 122 and may eachexpose the lower wiring pattern of the lowermost redistribution layer110-1.

The substrate pad dielectric layer 122 may have substrate pads 120therein. The substrate pads 120 may be disposed in the openings of thesubstrate pad dielectric layer 122. The substrate pads 120 may havetheir shapes that extend along inner lateral and bottom surfaces of theopenings. For example, the substrate pads 120 may fill the openings, andmay be provided on their bottom surfaces with recess regions that arerecessed toward the redistribution layers 110-1, 110-2, and 110-3 fromthe bottom surfaces of the substrate pads 120. For example, the recessregions of the substrate pads 120 may be central areas of respectivesubstrate pads 120 in a plan view.

A first seed layer 142 may be interposed between the substrate pad 120and the substrate pad dielectric layer 122. For example, the first seedlayer 142 may be in contact with the inner lateral surface of theopening formed in the substrate pad dielectric layer 122 and with anouter lateral surface of the substrate pad 120. The first seed layer 142may conformally cover the outer lateral surface, the bottom surface, andan inner lateral surface of the substrate pad 120. The first seed layer142 may have a lowermost surface coplanar with a bottom surface of thesubstrate pad dielectric layer 122.

A second seed layer 144 may be provided on the substrate pad 120. In therecess region, the second seed layer 144 may be formed to conformallycover the inner lateral surface and the bottom surface of the substratepad 120. For example, the second seed layer 144 may be formed toconformally cover the inner lateral surface and the bottom of the recessregion of the substrate pad 120 on which the first seed layer is formed.For example, the first seed layer 142 may be interposed between thesubstrate pad 120 and the second seed layer 144 on the inner lateralsurface and the bottom of the recess region of the substrate pad 120 asshown in FIG. 12.

External terminals 150 (referred to hereinafter as interposer terminals)may be provided on the substrate pads 120. The interposer terminals 150may be in contact with the second seed layers 144.

A first semiconductor chip 200 may be mounted on the redistributioninterposer 100. The first semiconductor chip 200 may be flip-chipmounted on the redistribution interposer 100. For example, the firstsemiconductor chip 200 may be mounted on the redistribution interposer100 through connection terminals 204 provided on chip pads 202 of thefirst semiconductor chip 200. The first semiconductor chip 200 may be,for example, a logic chip.

The chip stacks ST may be provided on the redistribution interposer 100.Each of the chip stacks ST may include a plurality of secondsemiconductor chips 720 that are stacked in a vertical direction on abase chip 710. An adhesive layer, such as a non-conductive film (NCF),may be provided between the second semiconductor chips 720 and betweenthe base chip 710 and the second semiconductor chips 720.

The base chip 710 and the second semiconductor chips 720 may each havethrough vias 722 that penetrate therethrough. Neighboring secondsemiconductor chips 720 may be connected to each other throughconductive pads electrically connected to their through vias 722 andbumps 724 between the conductive pads. The second semiconductor chips720 may be memory chips.

Each of the chip stacks ST may further include, on the base chip 710, achip stack molding layer 730 that covers the second semiconductor chips720.

The chip stacks ST may be mounted on the redistribution interposer 100.For example, each of the chip stacks ST may be electrically connectedthrough chip stack terminals 740 provided below the base chip 710 to alower wiring pattern of an uppermost redistribution layer 110-3 includedin the redistribution interposer 100. Therefore, the chip stacks ST maybe electrically connected to the first semiconductor chip 200 and/or theinterposer terminals 150.

A first molding member 300 may be provided on the redistributioninterposer 100. The first molding member 300 may cover the firstsemiconductor chip 200 and the chip stacks ST. The first molding member300 may include or may be formed of a dielectric material, such as anepoxy molding compound (EMC).

The redistribution interposer 100 may be mounted on a package substrate800. The package substrate 800 may have first pads 802 provided on a topsurface of the package substrate 800. The interposer terminals 150 ofthe redistribution interposer 100 may be electrically coupled to thefirst pads 802 of the package substrate 800. For example, the interposerterminals 150 of the redistribution interposer 100 may contact the firstpads 802 of the package substrate 800. The package substrate 800 mayhave second pads 804 provided on a bottom surface of the packagesubstrate 800. The second pads 804 may be provided thereon with externalterminals 810. The package substrate 800 may have wiring lines therein,and the first pads 802 may be electrically connected through the wiringlines to the second pads 804. The external terminals 810 may be mountedon an external substrate, such as a motherboard. For example, theexternal terminals 810 may be electrically connected to a circuit formedin the motherboard.

A second molding member 320 may be provided on the package substrate800. The second molding member 320 may cover top and lateral surfaces ofthe first molding member 300 and a lateral surface of the redistributioninterposer 100. The second molding member 320 may encapsulate theinterposer terminals 150.

FIGS. 13 to 23 illustrate cross-sectional views showing a method offabricating an interconnection structure according to some exampleembodiments of the present inventive concepts.

Referring to FIG. 13, a first carrier substrate 900 may be provided. Thefirst carrier substrate 900 may be a dielectric substrate including orformed of glass or a polymer, or may be a conductive substrate includingor formed of a metal. The first carrier substrate 900 may be providedwith an adhesive member on a top surface of the first carrier substrate900. For example, the adhesive member may include or may be a glue tape.

Sacrificial patterns 905 may be formed on the first carrier substrate900. For example, the sacrificial patterns 905 may be formed bydepositing a photosensitive material on the first carrier substrate 900,and then performing exposure and development processes on thephotosensitive material. The sacrificial patterns 905 may have theircircular shapes when viewed in a plan view. The sacrificial patterns 905may have their tetragonal cross-sections. No limitation, however, isimposed on the shapes of the sacrificial patterns 905.

Referring to FIG. 14, a first preliminary seed layer 146 may be formedon the first carrier substrate 900. The first preliminary seed layer 146may be formed to conformally cover the sacrificial patterns 905 and thetop surface of the first carrier substrate 900. The first preliminaryseed layer 146 may have a thickness of about 0.1 μm to about 1 μm. Thefirst preliminary seed layer 146 may include or may be formed of ametallic material that has a high wettability with an external terminal150 which will be discussed below. For example, the first preliminaryseed layer 146 may include or may be formed of copper (Cu), ruthenium(Ru), nickel (Ni), titanium (Ti), or tungsten (W).

Referring to FIG. 15, a preliminary dielectric layer 123 may be formedon the first carrier substrate 900. The preliminary dielectric layer 123may be formed to lie on the first preliminary seed layer 146 and tocover the sacrificial patterns 905. Therefore, the preliminarydielectric layer 123 may have a top surface that has protrusions on thesacrificial pattern 905. The preliminary dielectric layer 123 mayinclude or may be formed of a photosensitive polymer or aphoto-imageable dielectric (PID). The photosensitive polymer mayinclude, for example, one or more of photosensitive polyimide,polybenzoxazole (PBO), phenolic polymers, and benzocyclobutene polymers.

The preliminary dielectric layer 123 may be patterned to form a firstdielectric layer 122. For example, openings OP may be formed in thepreliminary dielectric layer 123, thereby exposing the first preliminaryseed layer 146. The preliminary dielectric layer 123 may be patterned byan exposure and a development processes. The exposure process may be anegative tone exposure process or a positive tone exposure process.Afterwards, a cure process may be performed on the preliminarydielectric layer 123. The openings OP may be formed on/above thesacrificial patterns 905. For example, when viewed in a plan view, thesacrificial patterns 905 may be positioned inside the openings OP. Thesacrificial patterns 905 may be spaced apart from inner sidewalls of theopenings OP.

Referring to FIG. 16, a second preliminary seed layer 148 may be formedon the first dielectric layer 122. The second preliminary seed layer 148may be formed to cover a top surface of the first dielectric layer 122,inner lateral surfaces of the openings OP, and a top surface of thefirst preliminary seed layer 146 exposed to the openings OP. The secondpreliminary seed layer 148 may have a thickness of about 0.1 μm to about1 μm. The second preliminary seed layer 148 may include or may be formedof titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalumnitride (TaN), nickel (Ni), or tungsten nitride (TW).

Referring to FIG. 17, a conductive layer 121 may be formed on the firstdielectric layer 122. The conductive layer 121 may be formed on thesecond preliminary seed layer 148, thereby filling the openings OP andcovering the top surface of the first dielectric layer 122. Theconductive layer 121 may be formed by performing a plating process inwhich the second preliminary seed layer 148 is used as a seed. Theconductive layer 121 may include or may be formed of a metal, such ascopper (Cu).

Referring to FIG. 18, the second preliminary seed layer 148 and theconductive layer 121 may undergo a planarization process to form firstseed layers 142 and substrate pads 120. The planarization process mayinclude or may be, for example, a chemical mechanical polishing (CMP)process. The planarization process may continue until the top surface ofthe first dielectric layer 122 is exposed. For example, the first seedlayers 142 may be formed by selectively removing the second preliminaryseed layer 148 from the top surface of the first dielectric layer 122,and the substrate pads 120 remaining in the openings OP may be formed byselectively removing the conductive layer 121 located at a higher levelthan that of the top surface of the first dielectric layer 122.

Referring to FIG. 19, a first redistribution layer 110-1 may be formedon the first dielectric layer 122. The first redistribution layer 110-1may be formed by forming a passivation layer 118 on the first dielectriclayer 122, forming a second dielectric layer 112 on the passivationlayer 118, forming openings that penetrate the second dielectric layer112 and the passivation layer 118 to expose the substrate pads 120, andforming a first barrier layer 116 and a first wiring pattern 114 in eachof the openings. The passivation layer 118 may be formed by performing adeposition process in which a dielectric material is deposited on thefirst dielectric layer 122. The deposition process may include or may bea chemical vapor deposition (CVD) process. The second dielectric layer112 may be formed by a coating process such as spin coating or slitcoating. The second dielectric layer 112 may include or may be formed ofa photosensitive polymer or a photo-imageable dielectric (PID). Forexample, the photosensitive polymer may include one or more ofphotosensitive polyimide, polybenzoxazole (PBO), phenolic polymers, andbenzocyclobutene polymers. The first barrier layers 116 and the firstwiring patterns 114 may be formed by forming a preliminary barrier layerand a conductive layer to fill the openings, and then performing aplanarization process on the preliminary barrier layer and theconductive layer.

Referring to FIG. 20, second and third redistribution layers 110-2 and110-3 may be formed on the first redistribution layer 110-1. Theformation of the second and third redistribution layers 110-2 and 110-3may be the same as or similar to that of the first redistribution layer110-1.

Referring to FIG. 21, a second carrier substrate 910 may be attached tothe third redistribution layer 110-3. The second carrier substrate 910may be a dielectric substrate including or made of glass or polymer, ormay be a conductive substrate including or made of metal. The secondcarrier substrate 910 may be attached to the third redistribution layer110-3 through an adhesive member provided on a top surface of the secondcarrier substrate 910. For example, the adhesive member may include ormay be a glue tape.

Afterwards, a resultant structure including the first and second carriersubstrates 900 and 910 may be turned upside down. For example, theresultant structure may be turned upside down to be in a position atwhich the third redistribution layer 110-3, the second redistributionlayer 110-2, and the first redistribution layer 110-1 are sequentiallystacked on the second carrier substrate 910.

The first carrier substrate 900 may be removed. The removal of the firstcarrier substrate 900 may expose the first preliminary seed layer 146.In this stage, top surfaces of the sacrificial patterns 905 may also beexposed.

Referring to FIG. 22, the first preliminary seed layer 146 may undergo aplanarization process to form second seed layers 144. The planarizationprocess may include or may be, for example, a chemical mechanicalpolishing (CMP) process. The planarization process may continue untilthe top surface of the first dielectric layer 122 is exposed. Forexample, the second seed layers 144 may be formed by selectivelyremoving the first preliminary seed layer 146 from the top surface ofthe first dielectric layer 122. The first seed layers 142 may be exposedby selectively removing the first preliminary seed layer 146 fromsidewall parts (see 126 of FIG. 2) of the substrate pads 120. When theplanarization process is performed, the sacrificial patterns 905 may bepartially removed. Therefore, the top surface of the first dielectriclayer 122 may be coplanar with uppermost surfaces of the first seedlayers 142, uppermost ends of the second seed layers 144, and the topsurfaces of the sacrificial patterns 905.

Alternatively, the first preliminary seed layer 146 may not be removedfrom sidewall parts (see 126 of FIG. 2) of the substrate pads 120. Asshown in FIG. 23, mask patterns 920 may be formed on the substrate pads120. The mask patterns 920 may cover the substrate pads 120 and mayexpose the top surface of the first dielectric layer 122. An etchingprocess may be performed in which the mask patterns 920 are used as anetching mask to selectively remove the first preliminary seed layer 146from the top surface of the first dielectric layer 122, thereby formingsecond seed layers 144′. Therefore, the first seed layer 142 may not beexposed. In this case, there may be fabricated an interconnectionstructure discussed with reference to FIGS. 4 and 5. The following willfocus on the embodiment of FIG. 22.

Referring back to FIG. 1, the sacrificial patterns 905 may be removed.The removal of the sacrificial patterns 905 may entirely expose thesecond seed layers 144 formed on recess regions of the substrate pads120. External terminals 150 may be provided on the exposed second seedlayers 144.

Thereafter, the second carrier substrate 910 may be removed.

By the process mentioned above, an interconnection structure 100 shownin FIG. 1 may be fabricated.

FIGS. 24 to 28 illustrate cross-sectional views showing a method offabricating an interconnection structure according to some exampleembodiments of the present inventive concepts.

Referring to FIG. 24, a first carrier substrate 900 may be provided. Thefirst carrier substrate 900 may be a dielectric substrate including orformed of glass or a polymer, or may be a conductive substrate includingor formed of a metal. The first carrier substrate 900 may be providedwith an adhesive member on a top surface of the first carrier substrate900. For example, the adhesive member may include or may be a glue tape.

Sacrificial patterns 905 may be formed on the first carrier substrate900. For example, the sacrificial patterns 905 may be formed bydepositing a photosensitive material on the first carrier substrate 900,and then performing an exposure and a development processes on thephotosensitive material. The sacrificial patterns 905 may have theircircular shapes when viewed in a plan view. The sacrificial patterns 905may have their tetragonal cross-sections.

A preliminary dielectric layer 123 may be formed on the first carriersubstrate 900. The preliminary dielectric layer 123 may be formed to lieon the first carrier substrate 900 and to cover the sacrificial patterns905. Therefore, the preliminary dielectric layer 123 may have a topsurface that has protrusions on/above the sacrificial patterns 905. Thepreliminary dielectric layer 123 may include or may be formed of aphotosensitive polymer or a photo-imageable dielectric (PID). Thephotosensitive polymer may include, for example, one or more ofphotosensitive polyimide, polybenzoxazole (PBO), phenolic polymers, andbenzocyclobutene polymers.

The preliminary dielectric layer 123 may be patterned to form a firstdielectric layer 122. For example, openings OP may be formed in thepreliminary dielectric layer 123, thereby exposing the sacrificialpatterns 905. The preliminary dielectric layer 123 may be patterned byan exposure and a development processes. The exposure process may be anegative tone exposure process or a positive tone exposure process.Afterwards, a cure process may be performed on the preliminarydielectric layer 123. The openings OP may be formed on the sacrificialpatterns 905. For example, when viewed in a plan view, the sacrificialpatterns 905 may be positioned inside the openings OP. The sacrificialpatterns 905 may be spaced apart from inner sidewalls of the openingsOP.

Referring to FIG. 25, a second preliminary seed layer 148 may be formedon the first dielectric layer 122. The second preliminary seed layer 148may be formed to conformally cover a top surface of the first dielectriclayer 122, inner lateral surfaces of the openings OP, and thesacrificial patterns 905 exposed to the openings OP. The secondpreliminary seed layer 148 may have a thickness of about 0.1 μm to about1 μm. The second preliminary seed layer 148 may include or may be formedof ruthenium (Ru), nickel (Ni), titanium (Ti), or tungsten (W).

Referring to FIG. 26, a conductive layer 121 may be formed on the firstdielectric layer 122. The conductive layer 121 may be formed on thesecond preliminary seed layer 148, thereby filling the openings OP andcovering the top surface of the first dielectric layer 122. Theconductive layer 121 may be formed by performing a plating process inwhich the second preliminary seed layer 148 is used as a seed. Theconductive layer 121 may include or may be formed of a metal, such ascopper (Cu).

The second preliminary seed layer 148 and the conductive layer 121 mayundergo a planarization process to form first seed layers 142 andsubstrate pads 120. The planarization process may include or may be, forexample, a chemical mechanical polishing (CMP) process. Theplanarization process may continue until the top surface of the firstdielectric layer 122 is exposed. For example, the first seed layers 142may be formed by selectively removing the second preliminary seed layer148 from the top surface of the first dielectric layer 122, and thesubstrate pads 120 remaining in the openings OP may be formed byselectively removing the conductive layer 121 located at a higher levelthan that of the top surface of the first dielectric layer 122.

Referring to FIG. 27, first, second, and third redistribution layers110-1, 110-2, and 110-3 may be formed on the first dielectric layer 122.The formation of the first, second, and third redistribution layers110-1, 110-2, and 110-3 may be the same as that discussed with referenceto FIGS. 19 and 20.

Referring to FIG. 28, a second carrier substrate 910 may be attached tothe third redistribution layer 110-3. The second carrier substrate 910may be a dielectric substrate including or formed of glass or a polymer,or may be a conductive substrate including or formed of a metal. Thesecond carrier substrate 910 may be attached to the third redistributionlayer 110-3 through an adhesive member provided on a top surface of thesecond carrier substrate 910.

Afterwards, a resultant structure including the first and second carriersubstrates 900 and 910 may be turned upside down. For example, theresultant structure may be turned upside down to have a shape in whichthe third redistribution layer 110-3, the second redistribution layer110-2, and the first redistribution layer 110-1 are sequentially stackedon the second carrier substrate 910.

The first carrier substrate 900 may be removed. The removal of the firstcarrier substrate 900 may expose the first seed layers 142. In thisstage, top surfaces of the sacrificial patterns 905 may also be exposed.

The sacrificial patterns 905 may be removed. The removal of thesacrificial patterns 905 may expose portions of the first seed layers142 formed on the recess regions of the substrate pads 120 as shown inFIG. 28.

Referring back to FIG. 6, external terminals 150 may be provided on theexposed first seed layers 142.

Thereafter, the second carrier substrate 910 may be removed.

By a process mentioned above, an interconnection structure 100 may befabricated as shown in FIG. 6.

According to some example embodiments of the present inventive concepts,an interconnection structure may include a first seed layer that blocksoxygen from being introduced into substrate pads from a third dielectriclayer or from outside and prevents the substrate pads from beingcorroded. An increased contact area and a high adhesive force may beprovided between a second seed layer and an external terminal. As thesubstrate pad is provided thereon with the second seed layer having ahigh wettability with the external terminal, the external terminal maybe rigidly attached to the substrate pad. Accordingly, above describedembodiments may be beneficial to provide an interconnection structurewith improved structural stability.

Moreover, the second seed layer may be provided to completely cover atop surface of the substrate pad, and the external terminal may be incontact with only the second seed layer. For example, the externalterminal may be in contact with only a single material layer. Therefore,surface stress may be alleviated in the interface between the externalterminal and the seed layer/substrate pad compared to a case in whichthe external terminal is in contact with a plurality of material layersat the same time. Accordingly, above disclosed embodiments may bebeneficial to provide an interconnection structure with improvedstructural stability.

Although the present inventive concepts have been described inconnection with some example embodiments of the present inventiveconcepts illustrated in the accompanying drawings, it will be understoodby one of ordinary skill in the art that variations in form and detailmay be made therein without departing from the spirit and essentialfeature of the present inventive concepts. The above disclosedembodiments should thus be considered illustrative and not restrictive.

What is claimed is:
 1. An interconnection structure, comprising: a firstdielectric layer; a wiring pattern formed in the first dielectric layer,a portion of the wiring pattern exposed with respect to a top surface ofthe first dielectric layer; a second dielectric layer on the firstdielectric layer, the second dielectric layer including an opening thatexposes the exposed portion of the wiring pattern; a pad formed in theopening of the second dielectric layer, the pad including a base partthat covers the exposed portion of the wiring pattern at a bottom of theopening and a sidewall part that extends upwardly along an inner lateralsurface of the opening from the base part; a first seed layer interposedbetween the second dielectric layer and a first lateral surface of thesidewall part, the first seed layer being in contact with the firstlateral surface and the second dielectric layer; and a second seed layerthat conformally covers a second lateral surface of the sidewall partand a top surface of the base part, the second lateral surface beingopposite to the first lateral surface.
 2. The interconnection structureof claim 1, wherein the first seed layer and the second seed layerextend onto a top surface of the sidewall part, and the first seed layerand the second seed layer are integrally formed into a single body. 3.The interconnection structure of claim 1, wherein the first seed layerextends along a top surface of the sidewall part and between the pad andthe second seed layer.
 4. The interconnection structure of claim 3,wherein the second seed layer extends onto the top surface of thesidewall part and covers the first seed layer.
 5. The interconnectionstructure of claim 1, further comprising a third seed layer on the basepart and between the second seed layer and the pad.
 6. Theinterconnection structure of claim 1, wherein a width of the sidewallpart is about 5% to about 20% of a width of the opening.
 7. Theinterconnection structure of claim 1, wherein the first seed layerincludes a metallic material whose ionization tendency is greater thanan ionization tendency of a metallic material included in the pad. 8.The interconnection structure of claim 1, wherein one of uppermost endsof the first seed layer and the second seed layer is located at a levelthe same as a level of a top surface of the second dielectric layer, theone of uppermost ends being most distant from the first dielectriclayer.
 9. The interconnection structure of claim 1, wherein the pad hasa U-shaped cross-section.
 10. The interconnection structure of claim 1,further comprising a solder ball on the pad, wherein the solder ball isin contact with the second seed layer on the second lateral surface ofthe sidewall part and on the top surface of the base part.
 11. Asemiconductor package, comprising: a redistribution substrate; asemiconductor chip mounted on the redistribution substrate; a moldinglayer on the redistribution substrate, the molding layer covering thesemiconductor chip; and an external terminal below the redistributionsubstrate, wherein the redistribution substrate includes: a firstdielectric layer; a wiring pattern formed in the first dielectric layerand electrically connected to the semiconductor chip, a portion of thewiring pattern exposed with respect to a bottom surface of the firstdielectric layer; a second dielectric layer formed on the firstdielectric layer and including an opening that exposes the exposedportion of the wiring pattern; a pad formed in the opening of the seconddielectric layer, the pad being in contact with the external terminal,the pad having a recess region that is recessed toward the firstdielectric layer from a first surface of the pad opposite the firstdielectric layer; and a first seed layer that conformally covers therecess region and the first surface of the pad, the first seed layerextending between the pad and the second dielectric layer.
 12. Thesemiconductor package of claim 11, wherein a lowermost surface of thefirst seed layer is coplanar with a bottom surface of the seconddielectric layer.
 13. The semiconductor package of claim 11, wherein thepad has a U-shaped cross-section.
 14. The semiconductor package of claim11, wherein the redistribution substrate further includes a second seedlayer on the recess region and the first surface of the pad, the secondseed layer vertically overlapping and contacting the first seed layer.15. The semiconductor package of claim 14, wherein the first seed layerincludes a metallic material whose ionization tendency is greater thanan ionization tendency of a metallic material included in the pad. 16.The semiconductor package of claim 11, wherein a width of the recessregion is about 80% to about 95% of a width of the opening.
 17. Thesemiconductor package of claim 11, wherein the external terminal fillsthe recess region and contacts the first seed layer.
 18. A method offabricating an interconnection structure, the method comprising: forminga sacrificial pattern on a carrier substrate; forming on the carriersubstrate a first dielectric layer that has an opening, the sacrificialpattern being in the opening; forming on the carrier substrate a firstseed layer that conformally covers the sacrificial pattern, a topsurface of the first dielectric layer, and an inner lateral surface anda bottom surface of the opening; forming on the first seed layer aconductive layer that covers the first dielectric layer and fills theopening; performing on the conductive layer a planarization process toform a pad that remains in the opening and to selectively remove thefirst seed layer from the top surface of the first dielectric layer;forming a second dielectric layer on the first dielectric layer; andforming a wiring pattern that penetrates the second dielectric layer andis coupled to the pad.
 19. The method of claim 18, before forming thefirst dielectric layer, further comprising forming on the carriersubstrate a second seed layer that conformally covers the sacrificialpattern and a top surface of the carrier substrate, wherein, in theopening, the first seed layer is in contact with the second seed layer.20. The method of claim 18, wherein the pad includes: a base part on atop surface of the sacrificial pattern; and a sidewall part that extendsfrom the base part along a lateral surface of the sacrificial pattern.